<?php
/**
 * PHPExcel
 *
 * Copyright (c) 2006 - 2011 PHPExcel
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * @category   PHPExcel
 * @package    PHPExcel_CachedObjectStorage
 * @copyright  Copyright (c) 2006 - 2011 PHPExcel (http://www.codeplex.com/PHPExcel)
 * @license    http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt    LGPL
 * @version    1.7.6, 2011-02-27
 */


/**
 * PHPExcel_CachedObjectStorage_Memcache
 *
 * @category   PHPExcel
 * @package    PHPExcel_CachedObjectStorage
 * @copyright  Copyright (c) 2006 - 2011 PHPExcel (http://www.codeplex.com/PHPExcel)
 */
class PHPExcel_CachedObjectStorage_Memcache extends PHPExcel_CachedObjectStorage_CacheBase implements PHPExcel_CachedObjectStorage_ICache {

    private $_cachePrefix = null;

    private $_cacheTime = 600;

    private $_memcache = null;


    private function _storeData() {
        $this->_currentObject->detach();

        $obj = serialize($this->_currentObject);
        if (!$this->_memcache->replace($this->_cachePrefix.$this->_currentObjectID.'.cache',$obj,NULL,$this->_cacheTime)) {
            if (!$this->_memcache->add($this->_cachePrefix.$this->_currentObjectID.'.cache',$obj,NULL,$this->_cacheTime)) {
                $this->__destruct();
                throw new Exception('Failed to store cell '.$cellID.' in MemCache');
            }
        }
        $this->_currentObjectID = $this->_currentObject = null;
    }    //    function _storeData()


    /**
     *    Add or Update a cell in cache identified by coordinate address
     *
     *    @param    string            $pCoord        Coordinate address of the cell to update
     *    @param    PHPExcel_Cell    $cell        Cell to update
     *    @return    void
     *    @throws    Exception
     */
    public function addCacheData($pCoord, PHPExcel_Cell $cell) {
        if (($pCoord !== $this->_currentObjectID) && ($this->_currentObjectID !== null)) {
            $this->_storeData();
        }
        $this->_cellCache[$pCoord] = true;

        $this->_currentObjectID = $pCoord;
        $this->_currentObject = $cell;

        return $cell;
    }    //    function addCacheData()


    /**
     *    Is a value set in the current PHPExcel_CachedObjectStorage_ICache for an indexed cell?
     *
     *    @param    string        $pCoord        Coordinate address of the cell to check
     *    @return    void
     *    @return    boolean
     */
    public function isDataSet($pCoord) {
        //    Check if the requested entry is the current object, or exists in the cache
        if (parent::isDataSet($pCoord)) {
            if ($this->_currentObjectID == $pCoord) {
                return true;
            }
            //    Check if the requested entry still exists in Memcache
            $success = $this->_memcache->get($this->_cachePrefix.$pCoord.'.cache');
            if ($success === false) {
                //    Entry no longer exists in Memcache, so clear it from the cache array
                parent::deleteCacheData($pCoord);
                throw new Exception('Cell entry '.$cellID.' no longer exists in MemCache');
            }
            return true;
        }
        return false;
    }    //    function isDataSet()


    /**
     * Get cell at a specific coordinate
     *
     * @param     string             $pCoord        Coordinate of the cell
     * @throws     Exception
     * @return     PHPExcel_Cell     Cell that was found, or null if not found
     */
    public function getCacheData($pCoord) {
        if ($pCoord === $this->_currentObjectID) {
            return $this->_currentObject;
        }
        $this->_storeData();

        //    Check if the entry that has been requested actually exists
        if (parent::isDataSet($pCoord)) {
            $obj = $this->_memcache->get($this->_cachePrefix.$pCoord.'.cache');
            if ($obj === false) {
                //    Entry no longer exists in Memcache, so clear it from the cache array
                parent::deleteCacheData($pCoord);
                throw new Exception('Cell entry '.$cellID.' no longer exists in MemCache');
            }
        } else {
            //    Return null if requested entry doesn't exist in cache
            return null;
        }

        //    Set current entry to the requested entry
        $this->_currentObjectID = $pCoord;
        $this->_currentObject = unserialize($obj);
        //    Re-attach the parent worksheet
        $this->_currentObject->attach($this->_parent);

        //    Return requested entry
        return $this->_currentObject;
    }    //    function getCacheData()


    /**
     *    Delete a cell in cache identified by coordinate address
     *
     *    @param    string            $pCoord        Coordinate address of the cell to delete
     *    @throws    Exception
     */
    public function deleteCacheData($pCoord) {
        //    Delete the entry from Memcache
        $this->_memcache->delete($this->_cachePrefix.$pCoord.'.cache');

        //    Delete the entry from our cell address array
        parent::deleteCacheData($pCoord);
    }    //    function deleteCacheData()


    /**
     *    Clone the cell collection
     *
     *    @return    void
     */
    public function copyCellCollection(PHPExcel_Worksheet $parent) {
        parent::copyCellCollection($parent);
        //    Get a new id for the new file name
        $baseUnique = $this->_getUniqueID();
        $newCachePrefix = substr(md5($baseUnique),0,8).'.';
        $cacheList = $this->getCellList();
        foreach($cacheList as $cellID) {
            if ($cellID != $this->_currentObjectID) {
                $obj = $this->_memcache->get($this->_cachePrefix.$cellID.'.cache');
                if ($obj === false) {
                    //    Entry no longer exists in Memcache, so clear it from the cache array
                    parent::deleteCacheData($cellID);
                    throw new Exception('Cell entry '.$cellID.' no longer exists in MemCache');
                }
                if (!$this->_memcache->add($newCachePrefix.$cellID.'.cache',$obj,NULL,$this->_cacheTime)) {
                    $this->__destruct();
                    throw new Exception('Failed to store cell '.$cellID.' in MemCache');
                }
            }
        }
        $this->_cachePrefix = $newCachePrefix;
    }    //    function copyCellCollection()


    public function unsetWorksheetCells() {
        if(!is_null($this->_currentObject)) {
            $this->_currentObject->detach();
            $this->_currentObject = $this->_currentObjectID = null;
        }

        //    Flush the Memcache cache
        $this->__destruct();

        $this->_cellCache = array();

        //    detach ourself from the worksheet, so that it can then delete this object successfully
        $this->_parent = null;
    }    //    function unsetWorksheetCells()


    public function __construct(PHPExcel_Worksheet $parent, $arguments) {
        $memcacheServer    = (isset($arguments['memcacheServer']))    ? $arguments['memcacheServer']    : 'localhost';
        $memcachePort    = (isset($arguments['memcachePort']))    ? $arguments['memcachePort']    : 11211;
        $cacheTime        = (isset($arguments['cacheTime']))        ? $arguments['cacheTime']        : 600;

        if (is_null($this->_cachePrefix)) {
            $baseUnique = $this->_getUniqueID();
            $this->_cachePrefix = substr(md5($baseUnique),0,8).'.';

            //    Set a new Memcache object and connect to the Memcache server
            $this->_memcache = new Memcache();
            if (!$this->_memcache->addServer($memcacheServer, $memcachePort, false, 50, 5, 5, true, array($this, 'failureCallback'))) {
                throw new Exception('Could not connect to MemCache server at '.$memcacheServer.':'.$memcachePort);
            }
            $this->_cacheTime = $cacheTime;

            parent::__construct($parent);
        }
    }    //    function __construct()


    public function failureCallback($host, $port) {
        throw new Exception('memcache '.$host.':'.$port.' failed');
    }


    public function __destruct() {
        $cacheList = $this->getCellList();
        foreach($cacheList as $cellID) {
            $this->_memcache->delete($this->_cachePrefix.$cellID.'.cache');
        }
    }    //    function __destruct()

}
